Don't call her Muriel

From working-class Sydney to Sunset Boulevard is quite a journey, but Toni Collette has made it look easy. Amanda Hooton meets the instinctive actor and hands-on mother who has taken the "t" out of can't.

You can tell Toni Collette is a celebrity because of her hair. It's blonde (art, not nature) and thick, and it has an excellent kink in it, swinging over her forehead and brushing her cheekbone. Even when celebrities shave their heads - as Collette has done on more than one occasion - you just know the great hair is there, waiting to spring forth again upon an astonished world.

Apart from the hair, Toni Collette has turquoise eyes with thick, dark lashes, long teeth, a great figure (including quite a big bottom), and is far friendlier than I expected. Back in the '90s, she seemed anxious and uncertain, often arriving late to interviews and sounding spiky and defensive.

These days, however, she's famous enough to do hardly any publicity, and perhaps this makes it easier for her to be calm with the journalists she does meet. And given that I manage to fling iced water all over the hotel lounge the moment we meet, and then burp loudly while she's trying to answer a question a few minutes later, she's actually under no obligation to be calm at all. But she is.

"Burp it up," she says cheerfully, pointing one long finger, with a short, purple-painted nail, towards my enormous stomach (I blame pregnancy for both aberrations). "Kids are the greatest, greatest thing," she says. "You love them so much, you just want to ..." She mimes a great big bite, as if eating a hamburger.

Collette has two children - daughter Sage, 4, and son Arlo, 1 - and she arrived on the set of her latest film, Mental, last June, when Arlo was only nine weeks old. "I don't know what I was thinking!" She shakes her head. "When I read the script I thought, 'Yeah, I totally get this, this is going to be easy' ... and it was not. Oh man. I was breastfeeding four or five times a night. And then I was on set, and trying to memorise six pages of dialogue every day."

Mental (which opens in Australia next month) is written and directed by Collette's old friend P. J. Hogan, who also wrote and directed her breakthrough film, Muriel's Wedding. Mental is an unusual work, to say the least. It's the story of five sisters, caught between their gentle, unravelling mother (Rebecca Gibney) and their sleazy politician father (Anthony LaPaglia), who are rescued, after a fashion, by a crazed Mary Poppins figure called Shaz, played by Collette. It's far darker than Muriel's Wedding, but eerily reminiscent of it. Both feature almost identically dysfunctional parents, similarly outcast kids, and exactly the same colour-saturated Queensland setting: Porpoise Spit in Muriel, Dolphin Heads in Mental.

According to Hogan, these references are deliberate, because the two movies are, in fact, "twin sisters. Or at least blood relatives." And this, in turn, is because, rather terrifyingly, both are based on his own life.

"I was one of seven kids, and when I was 12 our mother had a nervous breakdown and was institutionalised," he explains. "And our dad kept it from us. He was a local politician and running for an election. He was never father of the year, and he picked up a hitchhiker [the real-life Shaz] off the street and brought her home to look after us. She was one of the most inspiring, craziest people I've met in my life. She was always thinking she was being followed by the government, and by lesbians, and she had an irrational fear of mock cream: she went berserk in a cafe once when she thought someone had served it to her. She smashed a plate, which hit a chef."

There's no doubt that Shaz is the stuff that movies are made of (mock cream!), but you can't help wondering if Mental will suffer by comparison with Muriel; which was, after all, one of those peculiar, magical movies that strike a chord with audiences and continue to resonate for decades - so much so that at Collette's first appearance as Shaz, you find yourself thinking indignantly, "Muriel! What are you doing? You don't have a knife or a creepy dog or a florid mental illness! Get a hold of yourself!"

When it came to Shaz, "I always had Toni in mind, always," confesses Hogan, managing to make playing a rough-as-guts, mentally ill mock-cream obsessive sound like a compliment.

TONI Collette grew up in Blacktown, in Sydney's outer west. Her mum, Judy, worked for a courier company and her father, Bob, was a truck driver. She was a gregarious, dramatic kid - "that was me at the local Westfield, singing in the talent quest" - for whom the highlight of Saturday afternoons was the Bill Collins movie matinee. "I'd be there yelling, 'Quick, Mum! The movie martini's starting!' "

This background directly informs her acting. "Toni can play working class without comment and without an 'idea' of it," friend Rachel Griffiths once commented. "So many actresses come from the middle class and find it hard to play out of it. She reminds me of Hilary Swank in that way."

"I work instinctively," is how Collette describes it. "It's not clinical or technical: I don't do some weird method thing. I just want the character to be real, and however I can manage to do that is what I try to do."

She had no formal drama lessons as a child: her early oeuvre developed at Blacktown Girls High. But acting gripped her from the start. "It was like finding God, perhaps. I was so excited by it. In retrospect, I think, I was a bit hopeless at expressing myself, and here was a great tool for doing that."

Were her family not great expressers of emotion? Collette thinks about this carefully - she's always been extremely protective of her parents and two brothers (all of whom still reportedly live in the Blacktown area) - but after a moment concedes, "Maybe not ... It was fantastic to just be able to let it all out."

Nevertheless, it was her family who gave her self-reliance as an actor. Because she had no theatre background, she also had no expectations about how to approach her career. She was prepared to leave school at 16 to pursue acting, and to leave NIDA (to which she had been invited to apply) after 18 months at 19 to take a theatre role in director Neil Armfield's Uncle Vanya.

"I had fun there," she says of NIDA. "But I knew it wasn't the place for me. Maybe some people have potential that can be honed in that kind of environment, but my feeling is that in a creative life, you either have it or you don't. And if you don't, it's not something you can learn."

Collette's career moved swiftly from Chekhov to a role (alongside Anthony Hopkins) in Spotswood at 19, then to Muriel's Wedding at 20. But it wasn't an effortless rise. "For a long time I felt like anything I had to say on set or in a rehearsal room was insignificant," she admits. "I felt like everyone else was smarter than me."

In her 20s she struggled with bulimia and panic attacks, and although they were perhaps exaggerated in the media, both things were clearly signs that all was not well.

She looks past me, narrowing her eyes slightly at the panoramic Sydney Harbour views. "I think it was a lot of change, all at once." She tilts her head. "It was immense, immense! It just feels like someone else. It was so long ago."

Has she got better at dealing with things that used to bother her?

"I've got better at life! I think I'm more confident; and I'm allowing myself to enjoy my life more." She leans forward. "I think I used to be embarrassed to be an actor. Because I come from a family that doesn't do this kind of thing, sometimes it does feel kind of silly and indulgent. But as I've got older I do feel more comfortable saying it is important to me, and I am actually okay at it."

"Okay", in this case, means an AFI award and Golden Globe nomination for Muriel, an Oscar nomination for The Sixth Sense, and a Golden Globe and an Emmy for the Showtime TV drama United States of Tara, in which Collette plays a woman with dissociative identity disorder.

Collette grins. "My dad often says, 'I wish you were a sports person, because then I could cheer.' And it's so true! In this country, if someone wins a race, they talk about how proud they are, and how hard they've worked, and how they feel they've really achieved something. If you said that as an actor, people would throw rocks at you."

Toni Collette is married to musician Dave Galafassi, whom she met at a party in Sydney in 2002. He is five years her junior, and since their wedding in 2003 they've created a life in which, though based in Sydney, they travel with their children "as a unit" wherever Collette's work takes them. When they met, Galafassi was a drummer in Sydney indie band Gelbison, and he worked with her on her 2006 album, Beautiful Awkward Pictures.

Having specialised in portraying women alone on screen - often single mums or women in the grip of tormented relationships (The Sixth Sense, About a Boy, Japanese Story, Velvet Goldmine) - what has Collette learnt in real life about making love last? "Probably the big thing is that I'm not always right," she laughs. "But relationships do hold up a mirror, and you see yourself warts and all, which can give you the shits! But ultimately it helps you grow, and that's what life's about."

Unlike most people in their position, the couple don't employ a nanny. When Collette began work on United States of Tara, "we had our mums coming over to LA and helping out", but it's really Galafassi who makes Collette's acting possible. "I'm very conscious that if I didn't have him, I wouldn't be able to have a family and do what I do, and I actually need both."

Despite her happy marriage and stellar career and undeniable tonsorial success, not everything is perfect for Toni Collette. Even celebrities have bad-hair days, after all.

One such day occurred this May, with the release of a Commonwealth Bank advertisement featuring Collette, dressed in sackcloth grey (a sign?), with her hair scraped back (a sign!), reading a poem. TV viewers and bloggers were horrified. "Why would Toni sign up for an ad like this?" wrote one. "It's so out of character. No one ... understands why such a person with strong values and morals would ever do an ad for a bank of all things." "Toni appears to have sold her soul to the devil," wrote another. Most telling of all was one of the many YouTube parodies, in which a Commonwealth Bank sign is blown up by a missile while a voiceover intones, "You're terrible, Muriel."

"After Muriel's Wedding, Qantas came to me and wanted me to be the face of Qantas and be on the sides of buses and in cinema ads and have all these perks," says Collette in explanation. "And I said, 'No, I want to be a serious actor.' And then, soon after that, everyone was doing beauty products, watches, anything they could lay their hands on, and I was like, 'Oh no! What have I done!' "

These days, perhaps, when everyone from Cate Blanchett to George Clooney seems to have a product to spruik, you can hardly blame Collette for getting on the bandwagon.

Around the same time as the Commonwealth Bank contretemps, however, Collette attracted more criticism over a real-estate deal in Sydney's eastern suburbs, in which she and Galafassi allegedly pulled out of a $6.35-million house purchase in the exclusive suburb of Paddington after their own house (in equally exclusive Tamarama) failed to sell. The owners of the Paddington house are suing for non-performance in the NSW Supreme Court. But, again, Collette seems unfazed. "I love living in Sydney," she says firmly. "I don't give any of that [media scrutiny] stuff any credence, and it's nobody else's business."

In general, Collette seems pretty good at dealing with criticism. Even back in 2004, when Australian director Bruce Beresford called her "an actress who can only roll her eyes and grind her teeth", Collette herself seems to have been largely unaffected. "Look, if you're an artist of any kind, you do take things personally. It's inevitable. Because you're working from your soul. So perhaps if it had been earlier in my career it might have floored me; I might have been really upset. But I just don't care any more."

Toni Collette turns 40 this year. For many actors - both men and women - this is a perilous time, negotiating the move from "bright young thing" to "actor of substance". But Collette, whose own looks have never been of the extraterrestrially beautiful Angelina Jolie/Uma Thurman type, is untroubled by the transition.

"I want to have a long career, so I don't want to have to rely on something as temporary as looks. We're all going to age, and I'd like to do it naturally and gracefully."

It's good to see your forehead moving as you say that, I confess.

"Yes! My face moves! It's a weird phenomenon, this whole obsession with appearance. But that whole argument about there being no roles for women over 25 is just bullshit! I still feel like I'm getting offered really good roles."

For the rest of this year, she'll be working in London, Boston and LA, on projects alongside the likes of Steve Carell, Allison Janney and Sam Rockwell. She's recently finished Hitchcock, with Anthony Hopkins, Scarlett Johansson and Helen Mirren, and before that Jesus Henry Christ, in which she plays yet another single mum. "A single feminist mum," corrects Collette. Coming up is another Nick Hornby adaptation, called A Long Way Down, which sounds cheerful: "It's about four different people who go to the same rooftop to commit suicide on New Year's Eve."

Do you play a single mum?

"I do," says Collette gravely, then grins.

As well as acting, she adds, in the next few years she'd like to direct. Is it that she has particular stories she wants to tell, I wonder, or just a burning desire for control? "The burning desire for control, if I'm completely honest. I've just worked with so many directors who really haven't been that great, and you realise that ..." She pauses diplomatically. "Anyway. I'd like to tell a whole story rather than being part of a story."

This move will no doubt add another dimension to her first great love, acting; and as for her second, well, she has deep-laid domestic plans, too. "Living in hotel rooms in my 20s, I didn't have a kitchen, so I'm a really bad cook," she says. "My husband is an amazing cook, so he does most of it." She sits up, straightening her shoulders. "But I would, one day, like to reign over the kitchen!"